Step one - Make a poolish from small amount of yeast, flour and warm water (part of packet, 1/2 flour, 1/2 cup warm water). Let sit until it looks like this below. (10 minutes or more if you want).
Step 2 - Mix in dry ingredients ( 3 1/2 cups flour (1/2 cup in poolish), 1tbsp salt, 1tsp sugar, rest of the yeast packet. Stir it up.